1. Field of the Invention
The invention relates to a recording device having receiving means for receiving digital reception data which contain picture, sound and additional information, and having processing means for processing received reception data and for supplying digital recording data, a part of the digital recording data being formed by information data which contain additional information, and having recording means which includes at least two magnetic heads, mounted on a rotatably-supported head disc, for the recording of recording data in helical recording tracks on a magnetic tape, information data being recordable in at least two recording areas which differ as regards their positions in a helical recording track.
2. Description of the Related Art
Such a recording device of the type defined in the opening paragraph is known from International Patent Application No. PCT/IB 98/00130, published as WO 98/34225 and corresponding to U.S. Pat. No. 6,317,556, and takes the form of a video recorder. The known video recorder has receiving means formed by an input connector for receiving an MPEG transport stream which includes digital reception data(Moving Picture Experts Group, ISO/IEC DIS 13818.1). An MPEG transport stream can contain parallel picture and sound information of, for example, six television programs in so-called MPEG transport stream packets. Moreover, an MPEG transport stream can contain additional information relating to these six television programs in further MPEG transport stream packets in accordance with the DVB standard (Digital Video Broadcasting, ETS 300468 of February, 1998). In accordance with the DVB standard, additional information is transmitted, for example, in a so-called Selection Information Table contained in MPEG transport stream packets. Additional information can be, for example, information that a television program can be displayed in the 16:9 display format or that sound information of a television program supports Surround Sound. However, additional information can also relate to a title or the content of a television program.
The known video recorder further comprises processing means for receiving an MPEG transport stream and for processing the MPEG transport stream into recording data which can be recorded on a magnetic tape in accordance with the DVHS standard (Victor Company of Japan, No. 07015 of Jul. 25, 1997). MPEG transport stream packets which contain a Selection Information Table then form part of the recording data.
The known video recorder has recording means which enables recording data, including picture, sound and additional information, to be recorded in helical recording tracks on a magnetic tape of a magnetic-tape cassette. For this purpose, the recording means comprises a scanner having a head disc on which two magnetic heads, a magnetic head A and a magnetic head B, are mounted so as to be rotationally drivable. Head gaps of the magnetic heads A and B have different azimuth angles in order to reduce crosstalk from recording data recorded in adjacent tracks during the reproduction of the recording data. Due to the different azimuth angles, recording data recorded in a helical recording track by the magnetic head A can be reproduced only by the magnetic head A.
The recording means of the known video recorder is adapted to record recording data in helical recording tracks on a magnetic tape, a part of the recording data being formed by information data containing in additional information formed by MPEG transport stream packets. MPEG transport stream packets contain additional information received by the receiving means being inserted directly as information data in recording data to be recorded, as a result of which, information data are recorded in a plurality of recording areas which differ as regards their positions in a helical recording track. The position of a recording area containing information data therefore depends, basically, on the instant at which an MPEG transport stream packet containing additional information appears in the receiving data.
In order to reproduce recorded recording data, the known video recorder comprises reproducing means which includes the two magnetic heads A and B. The reproducing means reproduces recorded recording data with a normal reproducing speed, the transport speed of the magnetic tape during reproduction being the same as during the recording of recording data, and a helical reproducing track which is scanned by a magnetic head A or B covering only one helical recording track. The reproducing means also reproduces recording data at a multiple reproducing speed which is not more than 24 times as high (N=24), the transport of the magnetic tape being effected at a multiple not greater than 24 times the speed used for the recording of recording data, and a helical reproducing track scanned by a magnetic head A or B partly covering a maximum of 24 helical recording tracks at a time. In the case of a 24-fold reproducing speed, the magnetic head A or B scans 24 recording areas of 24 helical recording tracks then traversed. Due to the azimuth angle of the magnetic head A or B by which scanning is effected, recording data, which have been recorded for reproduction at the 24-fold reproducing speed, can be reproduced from 12 associated recording areas which differ as regards their positions in a helical recording track, so-called trick-play recording areas.
With the know video recorder, it has been found that information data recorded in recording areas which differ as regards their positions in helical recording tracks can be reproduced during reproduction of recording data at the normal reproducing speed. However, it has also been found that such information data are hardly ever reproducible during reproduction at a multiple reproducing speed. This is because a helical reproducing track traversed by a magnetic head A or B at a multiple reproducing speed nearly always scans other recording areas than the recording areas in which the information data are stored and whose positions in a helical recording track depend essentially on the instant at which an MPEG transport stream packet containing additional information appears in the receiving data.
It is an object of the invention to solve the aforementioned problems and to provide an improved recording device of the type defined in the opening paragraph. In a recording device of the type defined in the opening paragraph, this object is achieved in that detection means is provided for detecting additional information contained in reception data and for supplying received detected additional information, and in that additional information processing means is provided for processing received detected additional information and for supplying information data, and in that the recording means is adapted to record the information data supplied by the additional information processing means in an information data recording area which is always the same as regards its position in a helical recording track. This yields the advantage that information data, contained in receiving data and recorded in the information data recording areas, can be reproduced by a reproducing device both during a reproduction mode, in which the transport of the magnetic tape is effected with the normal reproducing speed, and during a reproduction mode, in which the transport of the magnetic tape is effected at a multiple reproducing speed. As a result of this, additional information, for example, the title or content of a television program, can also be reproduced together with picture and sound information at a multiple, for example, the 24-fold, reproducing speed. However, it is particularly advantageous that information data recorded in the information data recording areas can also be reproduced at particularly high reproducing speeds, such as, for example, the 96-fold reproducing speed.
It is to be noted that when, with the known video recorder, information data are recorded in trick play recording areas for reproduction at, for example, a 24-fold reproducing speed, as explained hereinbefore, these can be reproduced only at the 24-fold reproducing speed. Therefore, the information data must be recorded additionally for any multiple reproducing speed desired during subsequent reproduction, which is a substantial drawback. Furthermore, information data can be reproduced at a 24-fold reproducing speed at the most, which is also a substantial drawback.
In a recording device as defined above, it has proven to be advantageous that selection means is provided for selecting received detected additional information and for supplying selected additional information to the additional information processing means. This has the advantage that only additional information selected in accordance with given criteria is recorded as information data in information data recording areas. Such criteria can be stored, for example, in the selection means during the manufacture of the recording device.
In a recording device as defined above, it has proven to be advantageous that the selection means is adapted to select received detected additional information in dependence upon selection information applied to the selection means, and to supply selected additional information to the additional information processing means. This has the advantage that the selection means can use selection criteria which are defined by a user or which are dependent on the mode of operation of the recording device.
In a recording device as defined above, it has proven to be advantageous that the recording means is adapted to record the information data supplied by the additional information processing means in the information data recording area of each helical recording track. This has the advantage that information data can be reproduced continuously during a reproducing process and additional information contained in the information data can be detected very rapidly.
In a recording device as defined above, it has proven to be advantageous that the detection means is adapted to detect additional information contained in a Selection Information Table in reception data in accordance with the DVB standard. This has the advantage that additional information can be determined from receiving data in a particularly reliable manner.
In a recording device as defined above, it has proven to be advantageous that the at least two magnetic heads have Z different azimuth angles, and that reproducing means is provided for reproducing information data recorded in information data recording areas at a maximum N-fold reproducing speed, each of the at least two magnetic heads being capable of scanning a helical reproducing track which traverses N helical recording tracks. This has the advantage that information data recorded in information data recording areas by the recording device can be reproduced by the reproducing means of the recording device at an N-fold reproducing speed at the most.
In such a recording device, it has proven to be advantageous that partitioning means is provided for partitioning additional data which contain additional information into K=(N*Z)xe2x88x921 partitions of information data which can each be recorded in an information data recording area, and that the recording means is adapted to at least K times record the K partitions of information data, which can each be recorded in an information data recording area of a helical recording track, in total in at least K*K information data recording areas of at least K*K helical recording tracks. This has the advantage that all the information data forming additional data can be reproduced at a plurality of reproducing speeds up to the N-fold reproducing speed at the most, but that at low reproducing speeds, it is not necessary to reproduce information data from all the K*K helical recording tracks in order to reproduce all the additional data. For example, at the normal reproducing speed, only K information data from K helical recording tracks must be reproduced in order to reproduce all the information data forming additional data.
In such a recording device, it has proven to be advantageous that the partitioning means is adapted to define the value N of the maximum N-fold reproducing speed as the least common multiple of all the values X of X-fold reproducing speeds envisaged for reproduction. A user of the recording and reproducing device can then specify that information data containing additional information of a television program to be recorded, should be reproducible at a 2-fold, a 4-fold and a 12-fold reproducing speed in a reproducing process after the recording. The least common multiple of the values (x=2, X=4, X=12) is the value xe2x80x9c12xe2x80x9d, for which reason the partitioning means are adapted to set the value N=12. This has the advantage that optimum values N and K can be determined, which enable recorded information data to be reproduced very rapidly at least at all the preset and, if applicable, also any further X-fold reproducing speeds. In the example given above, information data can also be reproduced at a 3-fold and a 6-fold reproducing speed.
In such a recording device, it has proven to be advantageous that the partitioning means is adapted to generate partitioning identification data which identify the partitioning of the additional data into a plurality of K partitions of information data, that the recording means is adapted to record partitioning identification data together with associated information data, and that allocation means is adapted to allocate, during reproduction, reproduced partitioned information data in accordance with concurrently reproduced partitioning identification data so as to obtain reproduced additional data. This has the advantage that a reconstruction of the reproduced information data in order to restore the additional data partitioned prior to recording by the recording means is possible in particularly simple manner.